Children’s use of local and global visual features for material perception

Abstract

Adults can rapidly recognize material properties in natural images (Sharan, Rosenholtz & Adelson, 2009) and children’s performance (Balas, 2017) in material categorization tasks suggests that this ability develops slowly during childhood. In the current study, we further examined the information children use to recognize materials during development by asking how the use of local vs. global visual features for material categorization changes in middle childhood. We recruited adults and 5–10 year-old children for three experiments that required participants to distinguish between shape-matched images of real and artificial food. Accurate performance in this task requires participants to distinguish between a wide range of material properties characteristic of each category, thus testing material perception abilities broadly. In two tasks, we applied distinct methods of image scrambling (block scrambling and diffeomorphic scrambling) to parametrically disrupt global appearance. In the third task, we used Gaussian blurring to parametrically disrupt local features visibility. In each task, we also measured baseline response latency differences between age groups using a simple 2AFC color-matching task. Our key question was whether or not participant age affected performance (correct response latency) differently when local vs. global appearance was disrupted. Parametric variation in each task strongly affected performance (BF₁₀ > 10⁶ in all tasks). Once baseline RT differences across age were regressed out, participant age affected performance when Gaussian blurring and block scrambling were applied (BF₁₀ > 80 in each case), but not when diffeomorphic scrambling was applied (BF₁₀=1.2). Finally, only block scrambling led to an interaction between parametric appearance variation and age (BF₁₀=87.6). This pattern of results suggests that disrupting local and global visual features affects children’s performance in much the same way as it affects adults, with the exception of block scrambling, which we argue differs due to the addition of high spatial frequency artifacts to manipulated images.

Acknowledgement: NSF DLS 1427427